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Makoto Takahashi Masahiro Aoki Hiroshi Sato Tsukuru Ohtoshi Shinji Tsuji 《Optical Review》1996,3(6):484-486
The optimal structure of a laser diode monolithically integrated with a thickness-tapered beam expander waveguide is demonstrated by analyzing the relationship between fiber coupling efficiencies and radiation losses. It is also found that mode conversion loss is lowered in a ridge waveguide structure than in a buried hetero structure under equivalent fiber coupling. A fabricated ridge waveguide device based on this design shows threshold current as low as 16 mA and narrow beam divergences of 13° and 12°. 相似文献
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Fukumoto K Sakai A Oya T Nakazawa H 《Chemical communications (Cambridge, England)》2012,48(32):3809-3811
Desulfurization of N,N-dimethylthioformamide (Me(2)NCHS) by hydrosilane has been achieved under photo irradiation in the presence of a methyl iron complex. The reaction sequences have been proposed, in which silyl migration from Fe to S of thioformamide triggers the cleavage of a C=S bond to give a carbene-iron complex. This intermediate was isolated and characterized by X-ray analysis. 相似文献
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A method for large-scale first-principles molecular dynamics (MD) simulations on electrochemical systems has been developed by combining the effective screening medium (ESM) method with O(N) density functional theory (DFT). This implementation has been significantly simplified by the introduction of neutral atom potentials, which minimizes the modifications to existing DFT code. In order to demonstrate ability of this implementation, it has been applied to an electrochemical system consisting of a H-Si(111) electrode, which is a candidate anode for high-capacity Li-ion secondary batteries, and a propylene carbonate (PC) solvent to simulate how PC molecules in the vicinity of the electrode surface respond to an imposed electric field. The large-scale MD simulation clearly demonstrates that the combination of the ESM and O(N) DFT methods provides a useful tool for first-principles investigation of complicated electrochemical systems such as high-capacity batteries. 相似文献
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Isomerically pure syn-/anti-isomers of 2,8-dimethylanthradithiophene (DMADT) were synthesized in five steps and characterized using thermogravimetry, X-ray single crystal analysis, UV-vis absorption, and electrochemical measurements. The physical properties in solution were slightly different for each isomer, whereby the more obvious differences were observed in the solid state. A field-effect transistor using the anti-isomer showed a much higher performance than that using the syn-isomer. 相似文献
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Tsukuru Maeda Dr. Kazuishi Makino Masamichi Iwasaki Prof. Yasumasa Hamada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(39):11954-11962
The development of Ir‐catalyzed asymmetric hydrogenation of α‐amino‐β‐keto ester hydrochlorides is described. This reaction proceeds through a dynamic kinetic resolution to produce anti‐β‐hydroxy‐α‐amino acid esters in a high diastereo‐ and enantioselective manner. Mechanistic studies have revealed that this unique asymmetric hydrogenation proceeds through reduction of the ketone moiety via the five‐membered transition state involving the chelation between the oxygen of the ketone and the nitrogen of the amine function. The relationship studies between the hydrogen pressure and the stereoselectivity have disclosed two mechanisms dependent on hydrogen pressure. Under low hydrogen pressure (<15 atm), the reaction rate proportionally increased with the hydrogen pressure. However, under the high hydrogen conditions, the reaction rate exponentially accelerated along with the increasing hydrogen pressure, which suggests the participation of two or more of hydrogen atoms. 相似文献
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Dr. Yui Sasaki Koichiro Asano Dr. Tsukuru Minamiki Zhoujie Zhang Dr. Shin-ya Takizawa Dr. Riku Kubota Prof. Dr. Tsuyoshi Minami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(64):14525-14529
This work reports the design of a highly sensitive solid-state sensor device based on a water-gated organic thin-film transistor (WG-OTFT) for the selective detection of herbicide glyphosate (GlyP) in water. A competitive assay among carboxylate-functionalized polythiophene, Cu2+, and GlyP was employed as a sensing mechanism. Molecular recognition phenomena and electrical double layer (EDL) (at the polymer/water interface) originated from the field-effect worked cooperatively to amplify the sensitivity for GlyP. The limit of detection of WG-OTFT (0.26 ppm) was lower than that of a fluorescence sensor chip (0.95 ppm) which is the conventional sensing method. In contrast to the previously reported insulated molecular wires to block interchain interactions, molecular aggregates under the field-effect has shown to be effective for amplification of sensitivity through “intra”- and “inter”-molecular wire effects. The opposite strategy in this study could pave the way for fully utilizing the sensing properties of polymer-based solid-state sensor devices. 相似文献
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Naoto Ogiwara Takenobu Nakano Tsukuru Masuda Keiichiro Kushiro Madoka Takai 《Macromolecular bioscience》2023,23(5):2200486
3D structured cells have great drug screening potential because they mimic in vivo tissues better than 2D cultured cells. In this study, multi-block copolymers composed of poly(2-methoxyethyl acrylate) (PMEA) and polyethylene glycol (PEG) are developed as a new kind of biocompatible polymers. PEG imparts non-cell adhesion while PMEA acts as an anchoring segment to prepare the polymer coating surface. The multi-block copolymers show higher stability in water than PMEA. A specific micro-sized swelling structure composed of a PEG chain is observed in the multi-block copolymer film in water. A single NIH3T3-3-4 spheroid is formed in 3 h on the surface of the multi-block copolymers with 8.4 wt% PEG. However, at a PEG content of 0.7 wt%, spheroid formed after 4 days. The adenosine triphosphate (ATP) activity of cells and the internal necrotic state of the spheroid change depending on PEG loading in the multi-block copolymers. As the formation rate of cell spheroid on low-PEG-ratio multi-block copolymers is slow, internal necrosis of cell spheroid is less likely to occur. Consequently, the cell spheroid formation rate by changing the PEG chain content in multi-block copolymers is successfully controlled. These unique surfaces are suggested to be useful for 3D cell culture. 相似文献
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Dr. Tsukuru Minamiki Dr. Riku Kubota Yui Sasaki Koichiro Asano Prof. Tsuyoshi Minami 《ChemistryOpen》2020,9(5):573-581
Artificial receptor-based protein assays have various attractive features such as a long-term stability, a low-cost production process, and the ease of tuning the target specificity. However, such protein sensors are still immature compared with conventional immunoassays. To enhance the application potential of synthetic sensing materials, organic field-effect transistors (OFETs) are some of the suitable platforms for protein assays because of their solution processability, durability, and compact integration. Importantly, OFETs enable the electrical readout of the protein recognition phenomena of artificial receptors on sensing electrodes. Thus, we believe that OFETs functionalized with artificial protein receptors will be a powerful tool for the on-site analyses of target proteins. In this Minireview, we summarize the recent progress of the OFET-based protein assays including the rational design strategies for devices and sensing materials. 相似文献
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